Field of the Invention
The present invention relates to an engine system. More particularly, the present invention relates to an engine system including a turbocharger and an electric supercharger and deactivating a portion of cylinders by a cylinder deactivation (CDA) device depending on a driving region of a vehicle.
Description of Related Art
An engine of a vehicle combusts a mixture of air inflowing from the outside and a fuel with an appropriate ratio to generate a power.
In a process of generating the power by driving the engine, the external air for the combustion must be appropriately supplied to obtain a desired output and combustion efficiency. For this, a turbocharger as a device turbocharging the air for the combustion to increase the combustion efficiency of the engine is used.
In general, a turbocharger is a device that rotates a turbine by using pressure of exhaust gas discharged from an engine and thereby increases output of the engine by supplying high-pressure air to a cylinder by using rotational force thereof. The turbocharger is applied to most diesel engines and is has also recently been applied to gasoline engines.
The turbocharger includes a wastegate valve controlling an amount of exhaust gas that is exhausted from the cylinder to be supplied to the turbine. A cost of the wastegate valve used in the turbocharger is very high.
As another example of an intake boost device, an electric supercharger using a motor to drive a compressor to compress external air has been used. Since the electric supercharger is driven by a battery, there is little boost, and it mainly supplies supercharged air to the cylinder in a low speed and low load region.
In general, the turbocharger (hereinafter referred to as ‘a mechanical turbocharger’) operated by the exhaust gas has low responsiveness, and it is difficult to realize a high compression ratio because of a magnitude of a back pressure.
In general, in the electric supercharger used in the vehicle, since an output of the motor is limited, a boosting region is limited to a low and middle speed region.
Accordingly, development of an engine system of a new concept including both the mechanical turbocharger and the electric supercharger is required.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.